Nickel base superalloys have been developed for use in severe service conditions including corrosion, high temperature and mechanical operations. Typical examples include a group of recent patented alloys as defined in U.S. Pat. Nos. 3,865,581, 4,006,015, 4,110,110 and 4,194,909. Compositions of these alloys are shown in Table 1. Table 1 lists the broadest ranges of all elements required or optional as disclosed. The alloys appear to be closely related in compositions. The compositional variations among these alloys, although seemingly minor, are effective to the extent that each of the alloys is a distinctive alloy with physical and mechanical properties especially suited for a particular use. This situation is generally common in metallurgy and especially in the superalloy arts.